How did asp.net user ID get on my computer?

I joined asp.net to find this out. I  recently downloaded XP Service Pack 3. I have never heard of ASP.NET. I decided to change the picture on my startup screen. When I clicked user accounts, in addtion to my account and the guest account, there was one that I NEVER put on my computer. It was Asp.Net Machine A. It is listed as a limited account with password protection! I NEVER PUT THIS ONE MY COMPUTER! Where did it come from?
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